Self-locking fastener assemblies having cammed wedge locking surfaces are known in the art. See for example my prior patents: U.S. Pat. No. 5,626,449 issued May 6, 1997, for "Wedge-Locking Fastener Assembly with a Cammed Flange"; U.S. Pat. No. 5,409,338 issued Apr. 25, 1995, for "Wedge-Action Lock Washer Assembly Having Coupled Washers"; U.S. Pat. No. 5,203,656 for "Self-Centering, Self-Tightening Fastener"; and, U.S. Pat. No. 5,080,545 issued Jan. 14, 1992, for "Lock Washer Assembly Having Wedge Lock Action".
The fastener includes a nut and a specially formed washer. Typically, means are provided for retaining the washer with the nut to assist in connecting the fastener to a workpiece. In my prior co-pending patent application, I disclose such a fastener which included a cup-shaped washer having an integral annular cylindrical skirt that extends around the edge of the flange of the nut. Tabs extend radially inwardly from the periphery of the skirt over the flange in such a manner that the washer can move axially as well as rotate with respect to the nut to permit the wedge-locking cams to wedge the nut between the cams on the washer and the threads on the bolt on which the nut is fastened. When the nut is turned in a tightening direction, it tightens the washer on the workpiece. When the nut tends to rotate in the loosening direction, such as in response to vibration, the washer remains fixed but the nut becomes tighter in the manner described in my prior patents.
One of the problems in connection with using such self-locking fasteners is that occasionally it becomes necessary to loosen the fastener from the workpiece. This is usually achieved by connecting a tool on the back side of the workpiece to the head of the bolt and unloosening the bolt while holding the nut and the washer together as a unit. Occasionally it is impossible or difficult to reach the head of the bolt. It is desirable to remove the fastener without going through the difficulty of destroying the fastener.